Types and Preparation of Nanomaterials

By Kris WalkerNov 17 2015

Image Credits: shutterstock.com/KaterynaKon

Nanomaterials are, as defined by Standford University's Environmental Health & Safety Department as "materials with a minimum of one external dimension that ranges in size between 1-100 nanometers [2.]"  Yet according to the National Institute of Environmental Health Sciences, the definition of what nanomaterials are is not unanimous in the scientific world [3.]  Further, there are two basic types nanomaterials — those that are natural in occurrence and those that are man-made [3.] Manmade nanomaterials include four families. — Carbon based, metal based, dendrimers, and composites. From those many industries benefit including food and manufacturing and biomedical and pharmacology, naming but a few.

A Closer Look at the Four Families of Manmade Nanomaterial

Carbon Based Nanomaterial — generally speaking, carbon-based nanomaterials are made up of mostly carbon and form a variety of shapes. Mostly hollow tubes, cylinders, and ellipsoids [1.] They include nanotubes and fullerenes.

Carbon-based nanomaterials, such as nanotubes are simply the reconfiguration of carbon from a flat plane into a rolled tube shape [4.] Consider carbon as a chemical. It is denoted by the letter C. The chemical formula for a diamond is C. The two minerals very widely in strength, yet as a nanomaterial, soft graphite, become stronger simply by manipulating graphite's crystalline structure.

The creation or synthesis of nanotubes can occur in a variety of ways. Pattern Growth nanotubes are "grown [4.]" There are processes for ordered creation, Electric-field-directed growth and patterned growth [4.] The benefit of carbon nanotubes is that they offer amazing strength and structure to products and they conduct  heat and electricity, which is beneficial to technology development such as improved batteries [9.]

Metal Based Nanomaterials — These are metal based materials that we commonly regarded as quantum dots, nanogold, nanosilver and oxides with metal bases. Titanium dioxide is one such example. [1.] Metal based Nanomaterials are a focus of the biomedical and pharmaceutical industries [5.] The power here is the chemical binding or conjugated properties that metal-based nanoparticles offer. That power if found in the ability of multi-bond materials to be joined chemically with antibodies or pharmaceuticals [5.]

Preparation of metal-based nanomaterials synthesis through a variety of means such as microemulsions. According to the Journal of Pharmacy & BioAllied Sciences, the main technique used to create magnetic metal-based nanoparticles is through the manipulation of iron salts via chemical coprecipitation [5.] Metal based nanomaterials are used in healthcare such as contrast dyes that work with MRI and scanning devices for diagnostic purposes.

Dendrimers — Branched components that form polymers and whose surface exhibit chain ends suited for chemical manipulation as tools. Dendrimers are combinable to create hollow cavities or used as part of a catalysis [1.] Dendrimers represent a half step between molecular chemistry and polymer chemistry [6.] A fitting place considering that we prize these nanoparticles for their branched appendages. The creation or preparation of dendrimers is either via divergence or convergence [6.] Either the branches grow and then attach to the core or the branches grow from the core.

The process is via cascade reaction that is a natural reaction that nanotechnology has stolen from simply biology [6.] In the human body, protein synthesis is the building of more complex structures from parts. That is the same concept for Dendrimers. Dendrimers have an amazing capability, and their current application is through biomedicine with applications as anticancer drugs, pain management, and timed released medications such as a transdermal patch or in gene therapy.

Composites — As the word describes, this is a combination of nanoparticles or nanoparticles and other materials to form unique nanomaterials, that then go into the creation of products [1.] Thus far, the synthesis and properties of the first three families of nanomaterials and nanoparticles remain orderly and scientific. Composite nanomaterials remain orderly, but perhaps at a twisted level. These are not a single or group of particles — they are individuals of a population of particles with families, genus, and a ton of potential. These are the nanomaterials that make unique solutions possible - no pun intended.

Composites, like metallurgy, is a craft. The preparation of composites involves thermal reduction of metallic oxides and polyamide 6. [7.] Yet the use of PA6 is just one method of preparing composite nanomaterials. Electrospinning that morphs the physical object with the chemical solution to create single dimension composites that are somehow both organic and inorganic [8.]

Within these four families of nanomaterials exists a wide array of properties. Do you need a material that enables electrical configuration or that uses both mechanical and magnetic properties? Those are samples of the array of usefulness that nanomaterials bring to manufacturing, military technology, pharmaceuticals, and environmental industries.

There is much more to discover in the world of nanoparticles, and the potential of this industry is a doubled edged sword. For example, while metallic nanomaterials make internal diagnostics work, metals are typically harmful. More research can lead to better understanding and a more informed decision about how to use nanotechnology to benefit the planet, and mankind

References

1. AZO Nano Classification of Nanomaterials, the Four Main Types of Intentionally Produced Nanomaterials
2. Stanford Environmental Health & Safety
3. National Institute of Environmental Health Sciences
4. Stanford - Carbon Nanotubes: Synthesis, Integration, and Properties - Hongjie Dai.
5. Journal of Pharmacy & BioAllied Sciences - Iron Oxide Nanoparticles
6. National Institute of Health: Dendrimers: Synthesis, Applications, and Properties
7. Journal of Nanomaterials: Simple Method for Preparation of Composites Based on PA6 and Partially Exfoliated Graphite.
8. Science Direct - Materials Research Bulletin Volume 44, Issue 11 PP 2081-2086.
9. Phys.org Carbon Nanotubes find real world applications